The present invention is directed to a positioning work stop and more particularly to a positioning work stop for use with a machine tool in performing a precision machining operation and which informs the operator that the work piece is in its proper position for machining.
Computerized numerical controls (CNC) and other well-known machine tools are used to perform various machining operations. Before a machining operation can be performed, the work piece to be machined must be properly placed and held in a mounting fixture for positioning the work piece at a desired location relative to the machining tool. This is particularly important when the machining process is being performed on a CNC machine where the position of the work piece must align with the zero reference point programmed into the computer controls. A number of conventional positioning stops have been developed to accomplish the task of ensuring that the work piece is properly positioned.
Most such positioning work stops are relatively simple, manually operated devices whereby the machine operator installs the stop at a desired location and orientation, and sets the stop mechanism. When the work piece is placed in the mounting fixture and the surface makes contact with the stop, the machine operator knows that the work piece is in its proper position for machining. Unfortunately, work pieces often are jarred during setup or processing and slightly shift position and may no longer be in its proper position for machining. This is particularly problem some when machining highly precision parts. Further, when the work piece shifts out of position, the machining apparatus continues to operate that often results in a work piece being cut or machined out of specification thereby resulting in the work piece being scrapped or reworked. Further, this requires each work piece to be carefully inspected after the machining operation thereby significantly increasing the manufacturing time and cost of operation.
Accordingly, there is a need for a positioning work stop that can be used with conventional machining apparatus and operates to inform the machine operator that the work piece is in its proper position for machining and inform the machine operator if the work piece shifts out of its proper position and is no longer in its proper position on the positioning fixture. Further, a need exists for a positioning work stop that cooperates with the machine tool control system of the machining apparatus that stops the machining operation until the work piece is placed back into its proper position for machining or provide information necessary for the machine tool control system to adjust the machining operation to correct for the movement of the work piece.